Description
Product Usage Information
Cells are lysed in a urea-containing buffer, cellular proteins are digested by proteases, and the resulting peptides are purified by reversed-phase, solid-phase extraction. Peptides are then subjected to immunoaffinity purification using a PTMScan ® Motif antibody conjugated to protein A agarose beads. Unbound peptides are removed through washing, and the captured PTM-containing peptides are eluted with dilute acid. Reversed-phase purification is performed on microtips to desalt and separate peptides from antibody prior to concentrating the enriched peptides for LC-MS/MS analysis. CST recommends the use of PTMScan ® IAP Buffer #9993 included in the kit. PTMScan ® Ubiquitin Remnant Motif (K-epsilon-GG) Kit has a higher sensitivity and specificity magnetic bead version: PTMScan ® HS Ubiquitin/SUMO Remnant Motif (K-epsilon-GG) Kit in 10-assay ( #59322 ) or 3-assay ( #19089 ) formats, as well as a bead-only ( #34608 ) format.
Storage
Antibody beads supplied in IAP buffer containing 50% glycerol. Store at -20°C. Do not aliquot the antibody.
Protocol
Available protocols: PTMScan
Background
Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (2-4). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25a and bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (5-8). In this assay, the PTMScan Ubiquitin Remnant Motif (K-ε-GG) Antibody Bead Conjugate, a proprietary ubiquitin branch ("K-ε-GG") antibody with specificity for a di-glycine tag that is the remnant of ubiquitin left on protein substrates after trypsin digestion, is used to enrich ubiquitinated peptides from trypsin digested cell samples. This enrichment is followed by LC-MS/MS analysis for quantitative profiles of hundreds to over a thousand non-redundant ubiquitinated sequences.
Alternate Names
motif; PTMScan; ub; ubiquitin; ubiscan
